Agitation...

Discussion in 'B&W: Film, Paper, Chemistry' started by Ara Ghajanian, May 3, 2005.

  1. Ara Ghajanian

    Ara Ghajanian Member

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    I'm going to ask some very general questions. What's the deal with agitation during development? I've always done the 5 seconds every 30 seconds thing, but now I'm reading that in some cases people recommend 5 sec/minute, etc. Obviously, it must depend on developer and film, but is there a standard to follow and experiment with? What are the effects of under or over agitation? By the way, I shoot 35mm and 120 and develop in a Patterson tank (the black plastic one) I've had for years. Does the tank make a difference?
    Ara
     
  2. Claire Senft

    Claire Senft Member

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    It is much more dependant on how you like to do things than it is on a particular film and developer.
     
  3. Flotsam

    Flotsam Member

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    Less agitaion will generally give a lower contrast and vice versa.
     
  4. Peter Schrager

    Peter Schrager Subscriber

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    Agitation

    Ari-I now use a rotary drum on a motorized base for all my 120 negatives. I let the machine do all the work. I just kick back till the next changover. Negatives come out great. As a starting point I just reduce the times by about 15-20%.
    After that you need to fine tune. This way I don't worry about agitation because it's doing it full time!
    Best, Peter
     
  5. Loose Gravel

    Loose Gravel Member

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    Some developers like even more frequent agitation. I use one inversion every 15 seconds for PMK in a tank. I think this is because of bromide drag. As the film develops, bromide ions build up in the area of development. Bromide inhibits developement. So right where you need the developer working, bromide ions are inhibiting development. This can cause edge effects (a good thing) in small amounts, but as the bromide increases, it can streak the film. More frequent (not more total) agitation helps sweep the bromide buildup away.
     
  6. BarrieB

    BarrieB Member

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    Test yourself; Depending on the Dilution of the Developer, more agitation will increase the contrast. Depending on the ISO rating film development times can differ as well.
    Cheers Barrie B...... :smile: .
     
  7. Andy K

    Andy K Member

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    I have recently switched from agitating for 10secs/minute to agitating for 5secs every 30seconds because I find the latter improves contrast. My last addition to the standard gallery was developed usig this agitation method.
     
  8. rbarker

    rbarker Member

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    Don't forget the effect of the music you play in the darkroom. Faster-tempos often result in more vigorous agitation, even if the time is consistent. :wink:

    For 35mm and 120, I do 4 inversions with a 1/4 twist every 30 seconds. That's slightly less than 5 seconds, but that's what works for me.
     
  9. Nicole

    Nicole Member

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    I agitate for the full first minute and then only 2x every 30 seconds and am happy with the results I'm getting. Everyone to their own I guess.
     
  10. Ronald Moravec

    Ronald Moravec Member

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    Tried a lot of patterns and times over the years, different films and developers and films too. They all work.

    What doesn`t work is too infrequent and non random agitation. If you get problems, that is where to look first.

    My latest favorite is one roll in a two reel tank with an empty reel on the top using only enough liquid to cover the film during the 25 sec rest periods. Agitate by inversion so the film completely clears the developer twice in 5 sec,ie two inversions.
    This may seem weird, but this is how sheet film is developed.

    You can also use the same set up, but roll the tank 1 1/4 revolotions, two times each way, 5 sec /30. Bill Pierce wrote this up in a photo mag in the 60`s, so I can`t take credit for it, but will vouch for it`s effectiveness.